Lay is among the more confusing words in the English language. That is because the same word is used in the present tense for one definition and in the past tense for another. Even the definitions are somewhat similar. And lay and lie sound like twins.

Lay is a transitive verb that usually has to do with the action of putting something (other than one's self) somewhere, usually in a lower or resting position: "Lay it down." Laid is the word used for both past and past perfect tenses: "I laid it down." or "the hen has laid another egg." As a present participle, we use laying. Remember, in formal writing laid is never used for placing one's self, but is used for all other putting. The conjugations share the same definitions. Lay is of Old English origin and provoked no confusion, no problem. It was simple, more or less. (Old English had very complicated conjugations.)

Then, in 1066, William the Conqueror took over England. He and his followers proclaimed French as the national language, but the Anglo-Saxons refused to speak it. They claimed they were too dumb, an excuse the Normans readily accepted. Actually everybody learned both languages, but each proudly spoke only one. Eventually, about 600 years later, Modern English evolved.

Now, lie is an intransitive verb originating in Old French. It differs from "lay" in that it indicates reclining or resting. (After you lay something down, it lies there.) The only time "put" goes with "lie" is when the action is self imposed, as in "I lie down," or "Go lie down," which could translate to "Go put yourself down." Hardly anybody gets confused with the present tense of these two verbs. The big trouble came because lay is the past tense of the French lie. After you lie down, or have lain down, you lay there. How's that for confusing? By the way, the past perfect of lie is lain, and the gerund is lying.

It seems quite an imposition to have to discern between the present tense lay and the same word, lay, as the past tense of a different verb. The trick I use is to think of the Old English verb (lay, laid, laying) as action upon something, and therefore, it needs an object. The French verb (lie, lay, lying) no longer acts, it just reclines. Now, I'm not calling the French lazy, but perhaps they really knew how to relax.

Moreover, to make things even more confusing, the English speaking people adopted from the Greeks another lay (meaning "the people" as in layman) and Middle English adopted still another definition from Old French, and used lay a short, narrative poem that can be sung. But these are nouns, so no problem..

Also don't forget lie for telling a falsehood. That also came from Old English, and only after they were conquered would it have been confused with the French lie: They must have understood the difference, or usage would have tossed one or the other out" or merely abandoned it.

One of my favorite grammar jokes recalls a farmer being corrected by his scholar son. "I don't care whether I lay or lie down," he said. "I just want to know, when my hen cackles, is she laying or lying?"